<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
       *{margin: 0;padding: 0}
       ul{padding: 100px}

       /*
            找class为wrap元素底下的第二个子元素
            且这个子元素的class必须为item
        */
       /*.wrap .item:nth-child(2){color: deeppink}*/


       /*.wrap .item:nth-of-type(2){color: deeppink}*/
       .wrap div:nth-of-type(2){color: deeppink}
       .wrap strong:nth-of-type(2){color: deeppink}
    </style>
</head>
<body>
    <div class="wrap">
        <div class="item">item-1</div>
        <div class="item">item-2</div>
        <strong class="item">item-3</strong>
        <div class="item">item-4</div>
        <div class="item">item-5</div>
        <strong class="item">item-6</strong>
    </div>
</body>
</html>